Industrial control systems allow an operator to control and monitor the operation of industrial equipment and scientific devices. Such devices may include programmable logic controllers (PLCs), robotic systems, numeric control machines, automatic test systems, scientific analyzers, process controllers, and material handling machines. Previously developed control systems have suffered from several major defects, including the inability to process information quickly enough to meet system demands, and the lack of flexibility to work with varied applications.
The required speed of a control system is dependent upon the amount of data which must be processed by the control system, the complexity of the calculations which must be performed on the data, and the time in which the control system must respond to changing conditions. In order to increase the speed of their systems, control system manufacturers have increased their complexity, resulting in a two- or three-fold increase in speed. However, this increase has been insufficient to keep pace with increased demands. Furthermore, the increase in complexity has resulted in a decrease in flexibility.
Industrial applications vary widely and often change. Hence, industrial control systems must be able to permit future additions and changes. In an attempt to increase the flexibility of their systems, control system manufacturers have attempted to design their systems to fit the most popular applications, and permit some variance for the user to customize the system to meet a specific application's demands. This approach falls short in satisfying the widely varying requirements in industry and results in systems which do not completely meet a user's requirements.
From the foregoing, it can be seen that a need has arisen for an industrial control system having fast response capabilities and flexibility.